MerCruiser Trim Gauge Question

[1960 Starflite]

Are the trim gauges (dash) a volt meter or an OHM meter ? I understand that the trim sending unit is a variable resistor, so does the dash unit receive variable voltage or variable resistance?

I have an extra gauge that I could put to use to read variable suspension loads on a motorcycle project.

Yea, too cold here in Ohio to enjoy the boat or the bike. At least the bike is in my heated garage.

Thanks

 

[tpenfield]

Re: MerCruiser Trim Gauge Question

Are the trim gauges (dash) a volt meter or an OHM meter ? I understand that the trim sending unit is a variable resistor, so does the dash unit receive variable voltage or variable resistance?

I have an extra gauge that I could put to use to read variable suspension loads on a motorcycle project.

Yea, too cold here in Ohio to enjoy the boat or the bike. At least the bike is in my heated garage.

Thanks

Since the input voltage to the variable resistor (i.e. the sender) is a constant 12V +/-, the resulting voltage to the gauge will vary.

So the answer to your question is probably an ohm meter. Googling a schematic for the gauge does not seem to bring up much. so you may as well try it.

EDIT: I Googled the schematic for a "basic ohm meter", and it pretty much looks like the trim gauge circuit.

 

[UncleWillie]

Re: MerCruiser Trim Gauge Question

Since the input voltage to the variable resistor (i.e. the sender) is a constant 12V +/-, the resulting voltage to the gauge will vary. So the answer to your question is probably an ohm meter. .

The battery supplies a more or less Constant Voltage, The senders are a Variable Resistance (2 Wire).
The result will be a variable CURRENT.
All analog meters are Current (Amp) Meters at their hearts.

A Volt-Meter is an Amp-Meter in series with a Calibrating Resistor.
An Ohm-Meter is a Volt-Meter in series with a Constant Current source.

An Amp-Meter is Calibrated by placing a Shunt Resistance in Parallel with the basic meter.

 

[stonyloam]

Re: MerCruiser Trim Gauge Question

It is an analog voltmeter Voltmeter - Wikipedia, the free encyclopedia attached to the variable resistor of tha trim sender. Actually all your gauges are voltmeters (including the tachometer), unless of course you have a older boat with an ammeter. An ohmmeter uses an internal power source to measure the resistance in a circuit with no outside power applied. To use it on the trim sender you would unplug it and put one ohmmeter lead on each of the sender leads.

 

[1960 Starflite]

Re: MerCruiser Trim Gauge Question

Thanks so much for the replies. I have installed a hydraulic shock on my bike with adjustable pre-load via a pump. I need to read the position of the pre-load thru a variable resistor mounted within the unit. I thought the trim gauge would work fine for this mounted on the handlebars.

I hope the moderator does not pull this thread SORTA boat related

 

[stonyloam]

Re: MerCruiser Trim Gauge Question

Yeah that should work, however if the range of the resistors is significantly different the gauge may be either too sensitive or not sensitive enough. You might want to grab an ohmmeter and measure the min and max resistance of both resistors.

 

[tpenfield]

Re: MerCruiser Trim Gauge Question

Thanks so much for the replies. I have installed a hydraulic shock on my bike with adjustable pre-load via a pump. I need to read the position of the pre-load thru a variable resistor mounted within the unit. I thought the trim gauge would work fine for this mounted on the handlebars.

I hope the moderator does not pull this thread SORTA boat related

there is a non-boating technical topics forum, so worst case, it would get moved.